Chapter 7: Flashcards
What is the difference between Prokaryotes vs. Eukaryotes?
Pro- no membrane bound organelles, (sometimes has structures for photosynthesis.)
Euk- contains internal membrane bound organelles.
Which cell type is larger Prokaryotes or Eukaryotes?
Eukaryotes
What are examples of Prokaryotes?
What do
Bacteria and Archaea
Nearly all prokaryotes contain what?
Cell wall, and a membrane constructed via a phospholipid bilayer.
What do the Cell Wall in prokaryotes do?
- Protect from things
- prevents bursting or swelling as a result of osmotic pressure.
What kinds of environments do bacteria often find themselves in?
Hypotonic
What are the two forms in which DNA comes in Prokaryotic cells?
- ) Chromosomal- large circular molecule of DNA.
2. ) Plasmids- smaller portions of DNA, that hold important genes.
What is conjugation?
Plasmids exchange genes with other similar forms of bacteria.
What and Where is the nucleoid region of a bacteria molecule found?
- The region of cytoplasm within a bacterial cell where the circular chromosome is found.
What is the idea of super-coiling?
- If u take a circular molecule ( like the DNA found in bacteria) and it is twisted, than that will automatically cause that molecule to wrap up.
- So it continues to coil and allows it to occupy a relatively small volume.
What cells contain Ribosomes?
All cells.
What is the function of RNA?
To make new proteins.
What are the sub-units of RNA?
Large-
Small-
Composed of lots of individuals pieces
How do the ribosomes of prokaryotes and eukaryotes differ?
the specific components that there ribosomes are constructed of. (proteins such)
Hoe can Rna be used diagnostically?
You can look and see what types of rRna’s make up the cells ribosomes and determine if it is prokaryotic or eukaryotic.
What are the different classes of appendages seen on prokaryotes?
Flagellum- really long and mobile (motile) appendages, that are large, complex, and multicellular subunit proteins that span the bilayer and cell wall. ( like a boat prop) (movement)
Fimbriae- long spiky looking structures that serve to anchor the prokaryote ( cell to cell or cell to environment anchoring).
Contrast: Size?
Euk- approx 10-100 mico meters
Pro- 1 mico meters
Contrast: Membrane-bound nucleus?
Pro- no
Euk- yes
Contrast: other internal organelles?
Pro- rarely
Euk- many
Contrast: Chromosomes?
Pro- single circular loop of DNA with few complexed proteins.
Euk- multiple linear chromosomes with lots of complexed proteins
Contrast: Ribosomes?
Pro- smaller, less complex
Euk- larger, more complexed
what are the differences between cytosol and cytoplasm?
Cytosol- fluid, water, watery component of which stuff is dissolved within the cell
Cytoplasm- anything inside the cell membrane
what is an organelle?
small membrane bound structure within a cell that contains the proteins necessary for a very particular structure.
Most of the organelles with plant and animal cells are the same (T/F)?
- If T/F explain the similarities and or differences?
(as described by Greedy Sneed douchebag Reedy)
- T
- Plant cells got: cell wall, chloroplast, and a vacuoles!!!!
What is the largest organelle in a eukaryotic cell?
The nucleus
T/F the nucleus is contained within a single membrane?
False, double membrane structure.
What is the only organelle we can see with a standard light microscope?
Nucleus
What are the nuclear pours?
The point where the double membrane meets creating passage ways.
What is found within the nucleus?
Chromosomes!!! I have 35 myself !!!
How do the chromosomes of Eukaryotes vs Prokaryotes differ?
Euk- linear stranded, almost always more than one.
Pro- circular
What are the areas of higher density within the nucleus known for and as?
- Nucleolus, lots of ribosomal RNA is produced.
- areas of densely packed chromosomes.
What are the mitochondrion?
- football shaped structures located floating throughout the cell.
- double membraned structure
What are Cristae and what membrane bound organelle do they belong to?
- Larger inner folds of the mitochondria, thus increasing its surface area of the inner mitochondrial membrane
- literally a chick with giant meat flaps, like Hella surface area and stank…
What is the role of the mitochondria and where are it’s important internal structures located at?
- produce ATP
- structures are located in the cristae
What is the mitochondrial matrix?
- The fluid filled spaces in between the cristae.
T/F mitochondria have DNA within them?
Correct Brotha
In animal cells what cellular structures house DNA?
In plant cells what cellular structures house DNA?
- ) Mitochondria and nucleus.
2. ) chloroplast, nucleus, and algae have mitochondria.
Peroxisomes?
small spherical organelles found right at the cell periphery.
- what we have classified as peroxisomes is likely a multiple sub types of organelles that look a like.
- Where oxidation reactions occur
What is universal peroxisome function?
the peroxisomes is the site where hydrogen peroxide is contained and then degraded in a controlled fashion called catalase.
- which produces free radicals.
Where do we find Ribosomes (eukaryotic cells)?
- floating in the cytosol
- anchored on the surface of the Rough endo-plasmic reticulum.
- Nucleus synthesis ribosomes
What is the function of the rough ER?
- Protein synthesis.
What is the Smooth ER?
Primarily new lipid metabolism
BOBBY FUCKING SHMUURRDDAAA says that in some cells the smooth er can …?
detoxify against certain cell type (hydrophobic)
In a liver cell you’d likely find a high concentration of what?
BoBBy Shmurdra…jk
Smooth Endoplasmic reticulum
What is the golgi apparatus?
- network of membranes that lay very close to the rough er
- receives vesicles containing proteins.
Where are the proteins received on the Golgi apparatus?
- “cis” face of the Golgi apparatus or point facing the rough er.
What is the trans phase of the Golgi?
- The trans phase of the Golgi is the last fold of the golgi.
- where the OG vesicle containing protein is repacked into in a new vesicle right outside the trans.
What are lysosomes?
- Spherical cells found near the cell membrane.
- only found in animal cells.
- Basically the recycling cell. ( take in large cellular macro-molecules and break them down into smaller pieces and them export those pieces into the cytosol to be reused.)
What allows lysosomes to act as recycling cells?
They are packed full of a category of enzymes called acid hydrolases.
What are hydrolases?
An enzyme that carries our hydrolysis reactions. ( all of the biological macro molecules are broken down this way)
What are acid hydrolases?
hydrolases that only fold and work properly in an acidic environment.
What is the Ph of the lysosomes?
4-5, so it in fact uses acid hydrolases.
What is important about the acidic environment of the lysosome?
- ) hydrolysis reactions are more efficient in an acidic environment.
- ) acts a fail safe, if the hydrolases were let loose in the cytosol they could do lots of cellular damage
How is the acidic environment within a lysosome with held?
- Proton pumps
How do materials get delivered to the lysosome?
- ) Receptor-Mediated endocytosis: When enough molecules bind to the membrane it is then pinched inward and is brought into the cell in a new vesicle (endocytic vesicle). Next it is acidified until it reaches the stage of a lysosome.
- how cells bring in cholesterol. - ) Phagocytosis: cell encounters a larger structure in its extra-cellular-fluid. It then enters the cell and is pinched off thus creating a phagosome. The phagosome then gets delivered into a lysosome to be degraded.
- immune system is good at this. - ) Autophagy: using internal materials and delivering them to a lysosome.
- This can happen on a large scale or a small scale.
- The cell can build a new membrane around the damaged cell, and thus creates an Autophagosome.
- Then the autophagosome gets delivered to a lysosome.
Which types of cells rely more heavily on autophagy than any other cell?
Cancer cells.
Are lysosomes present in plants?
- No they are not.
What is the plants equivalent of a lysosome and what is that biddie’s functions?
- Vacuoles, they can be very large and look like large bags of fluid.
1. ) Storage: pigments, waste, salts, minerals, nutrients, pigments, and toxins
2. ) Recycling: similar to lysosomes
3. ) Structural: maintain the plant’s turgor pressure
What is the primary function of chloroplast?
- carry out photosynthesis.
What are the internal structures of chloroplasts.
- double membrane structure.
- Large stacks of membranes = thylakoids
- fluid filled area outside the thylakoids= stroma
- a place were thylakoids are stacked = granum
How are chloroplast and mitochondria similar?
- major energy producers for the cell
- contain their own genome
What is the importance behind the plant cell wall?
- ) plants lack internal structural mechanisms like bone, so the rely on the cell wall for rigidity and shape.
- ) Also allows two adjacent plant cells to stick together.
Cellular structure reflects its?
- Function, EX: an animals pancreatic cell has a large rough er so it can generate more proteins, as that is the major responsibility of that organ.
What are is steps involved for an organellar protein to reach its organelle?
- ) - “Molecular address” on that proteins, that is specific to the location of the organelle.
- ) - “Receptor” for the proteins that have a particular molecular address.
- ) system (pour) in the organelle membrane that allows that protein to get across.
What is a molecular address?
Small stretch of amino acids folded into a shape.
- Unique structural form on a protein, that specifically shows what organelle or protein it belongs to.
What is a nuclear protein?
A protein that functions within the nucleus.
Where are nuclear proteins made?
Ribosomes that are floating in the cytosol
What is the system that allows for nuclear proteins to enter the nucleus?
Nuclear pours- large protein complexes that span the inner and outer membrane.
T/F are nuclear pours highly regulated?
True they are highly regulated, and only open and close in response to certain stimuli
How do we determine the molecular address of a protein?
Experiment:
Hypothesis: nuclear plasmin must have some kind of a unique address on it, and it must identify it as some kind of a nuclear protein.
Goal: find the unique aspect of it that makes it a nuclear protein.
How do we determine the molecular address of a protein?
Experiment:
Hypothesis: nuclear plasmin must have some kind of a unique address on it, and it must identify it as some kind of a nuclear protein.
Goal: find the unique aspect of it that makes it a nuclear protein.
Approach: Broke the protein up into two parts: ( the tail and the core),
- used dye and placed them in sperate containers, each was injected into the cytoplasm of cells.
Theory: one of the two fragments that contains the molecular address will enter and the other will not.
Conclusion: the tail fragment readily entered the nucleus while the core didn’t.
Further steps: break the tail fragment into smaller fragments, and do this until you cannot get any smaller.
What type of protein contains an NLS?
Nuclear protein
What is the NLS (nuclear localization signal)?
What step does it represent in getting nuclear proteins into the cell?
Stretch of roughly 16-17 amino acids, in a mostly basic amino acid.
-This folds up into a really unique shape, that serves as a flag as to it being a nuclear protein.
—————————————–
Step 1.
What is importin?
What step does it represent in getting nuclear proteins into the cell?
- it is a protein in the cytoplasm, that is an intracellular receptor for proteins with an NLS.
- then importin delivers the protein with the NLS that binded to it… to the nuclear pour complex.
step 2.
What is the nuclear pour complex?
What step does it represent in getting nuclear proteins into the cell?
- ## are way of getting cargo across the nuclear membrane and into the nucleus.
Once you get your nuclear protein into the nucleus, how do we get the importin back out.
Importin binds to Ran-GTP.
What are RAN proteins?
Ran is an example of G protein.
What is a G protein?
- Bind to either GTP or GDP.
- Shape of protein is determined by what guanine group they are bonded to
How does RAN-GTP assist in moving importin out of the nucleus?
- When importin binds the RAN-GTP, it causes the importin to loose ahold of the nuclear protein.
- Then the RAN binds to the nuclear side of the nuclear pour complex and causes it to open itself up.
- Then delivers importin to the cytoplasm, and then GTP is hydrolyzed to GDP and thus importin dissociates.
What step is RAN-GTP of getting nuclear proteins into the cell?
3rd.)
What are the basic steps to moving a protein through the endomembrane system?
- ) Being synthesized by ribosomes on the rough er.
- ) - then the protein enters the rough er and is packaged into a vesicle.
- ) - the protein within the vesicle moves to the cys Golgi apparatus.
- ) -further through the Golgi apparatus being modified in various ways as it goes.
- ) - it is packaged into a new vesicle in the trans Golgi and then delivered to its final destination.
What is the endomembrane system?
A group of cellular structures that function together as a unit, i.e. there is a lot of movement between these cellular structures.
Rough ER, Smooth ER, Golgi, transport vesicles, lysosomes, plasma membrane
What Cellular organelles are considered to apart of the endomembrane system?
- rough er, Golgi apparatus, lysosomes, cellular membrane, smooth er, transport vesicles.
How did we discover learn the steps involved in the process of the endomembrane system?
- George Palade: pulse-chase experiment: very good at tracking the movement of something through a pathway, when you can’t directly tell what is happening.
- ) they picked a cell from the pancreases, because it is an area that produces lots of proteins.
- ) Grow cells in normal or typical media, then replace media with some that contains radioactively labeled aminos.
- ) leave for approax. 5 minutes than replace with normal media.
- ) Therefore, any proteins produced in this time frame are radioactively labeled ( so you can see) (pulse) .
- ) How long you can wait before you end the experiment= chase.
- ) they repeated and manipulated the chase to get a very robust pathway in which proteins moved through the cell.
What were the results of the cellular pulse-chase expt?
- right after the pulse = proteins were found in the rough Er
- Short chase= most of the labeled proteins in the Golgi apparatus.
- Longer chase= most of the proteins were in transport vesicles or had been secreted.
How do proteins get into the rough Er in the first place?
- ) - Er signal sequence is synthesized.
- ) - ER signal sequence binds to the signal recognition particle. (SRP)
- ) SRP binds to receptor (Translocon)
- ) Once the pair (SRP + ER signal sequence) binds to the Translocon it signals the SRP to dip.
- ) Following the release of SRP, protein synthesis resumes and the rest of the protein is made and pushed back through the translocon.
- ) This puts it back into the Rough ER, the protein sequence is cut off and the protein folds.
-Er signal sequence?
Stretch of amino acids at the amino terminus (equivalent of NLS, but just meant for Rough ER)
Where is SRP located
Cytoplasm
Where does the second level of nuclear membrane sorting occur?
Trans Golgi apparatus.
How many molecular address do nuclear proteins contain?
2, this one gets it to the correct vesicle
What is the cytoskeleton?
- network of fibers that runs throughout the cell, and gives the cell its internal shape/structure.
- Can be very important in movement/function.
- Can also play a role in movement.
What are the three kinds of cytoskeletons seen in eukaryotes?
- Microfilaments: composed of ( Actin)
- Microtubules: composed of ( Tubulin dimer)
- Intermediate filaments ( Various)
What are microfilaments?
How many actins are in a microfilament?
- Form of cytoskeleton
- they are long ( 7-9nm), skinny and composed of actin.
- assembles into a polymer
- two actin
- 2
What dictates the manner in which actin filaments bundle and organize?
- The proteins that they associate with.
T/F actin filaments are highly dynamic?
True, they are easy to tear down and rebuild.
Myosin is what form of a protein, and what does it serve to do?
Motor protein- binds to something in the cytoskeleton and hydrolyzes atp and uses that energy to move along the cytoskeleton.
What are actin myosin interactions important for?
- muscle contraction
- cell division
- cytoplasmic streaming in plants
what are Intermediate filaments?
- slightly larger in diameter
- very stable
- difficult to make and highly unlikely to be broken down.
- long protein strands that are robust and rope like.
What are some of the differing forms of intermediate filaments?
- Skin ( keratin)
- neurons ( long axon projections #nuerofilaments)
- muscle tissue
- lamin ( inside the nucleus under its membrane)
What is the one intermediate protein that all eukaryote make?
- lamin
What are Microtubules?
- largest out of the eukaryotic filaments (25 nm across)
- a-b tubulin
- hallow
- highly dynamic structure.
- central organizing cite within the cell.
What does it mean to be a highly dynamic structure?
- Contains a plus end and a minus end.
- end that is more likely to add sub units an one that is likely to lose sub-units.
What is a centrosome?
What about in relation to a microtubule?
- All cells contain at least one.
- composed of two centrioles that are surrounded by a haze of proteins.
- growth branch’s out from this point
- anchors the minus end of microtubules so they don’t shrink.
What is the function of the motor proteins in microtubules
( Kinesin and dynein) are microtubule motor proteins
serves to move the microtubule towards plus/minus end.
What is the difference between Kinesin and Dynein?
Kinesin- motor protein that moves its cytoskeleton towards the plus end of the microtubule.
(away from the centrosome)
——————————————–
Dynein- motor protein that moves its cytoskeleton towards the minus end toward the minus end of the microtubule.
(Toward the centrosome)
What are the two cellular appendages discussed that are microtubule based in their structure?
- Cilia: tend to be very short, uses a sweeping like motion to make it through various environments. Sweeps liquid over an environment
( small microtubule appendages)
——————————————- - Flagellum: tend to be very long, uses a pulse like movement pattern to move through watery environments.
( Sperm cells are the only ones in humans)
What is the highly organized microtubule structure seen in a cross section of a cilia and flagella?
- axoneme; highly organized microtubule structure inside of cilia or flagella that is composed of several rings or doublets.
- Key for coordinated bending and cilia/flagellum movement.
t/f Bacteria has a cytoskeleton?
false, they have proteins that assembly very similarly to eukaryotic cytoskeletons.
microfilaments=actin filaments?
Yep.
What is a spoke?
Flexible protein found in the axoneme, connecting the dynein arms.
